


When You Know, You Know

by CaffeinatedFlumadiddle



Category: Merlin (TV)
Genre: Alternate Universe - Canon Divergence, And is just like 'he knows about my fucking magic damnit', Attempt at Humor, Canon Era, Fluff, Fluff and Humor, For once I'm torturing Merlin and not Arthur lol, Gen, Humor, M/M, Magic Revealed, Merlin is stressed that Arthur knows all these little things about him, Merlin's Magic Revealed (Merlin), Not Canon Compliant, THERE ARE SO MANY HUMOR TAGS, meanwhile Arthur is just trying to live his best life, so that's some good news, which is kinda reasonable, wondering wtf Merlin's problem is
Language: English
Status: Completed
Published: 2020-04-02
Updated: 2020-04-02
Packaged: 2021-03-01 03:54:23
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,439
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/23428786
Author URL: https://archiveofourown.org/users/CaffeinatedFlumadiddle/pseuds/CaffeinatedFlumadiddle
Summary: "You can take Daisy out to fetch the cloak-""How do you know that?"Arthur closed his eyes, expression riddled with irritation before turning to look at Merlin expectantly."Know what?"“The mare I use. You know I call her Daisy? I never told you that." Merlin explained. Arthur stared for a few moments. He could see the flicker of emotions pass easily over him. Anger, annoyance, exasperation, indignance, and finally acceptance...AKA the Five Stages of Grief (Pendragon Edition)."You talk to the horse.” He pointed out. Merlin narrowed his eyes.“I whisper to the horse.""...am I supposed to not hear it?” Arthur asked. Merlin wondered how likely it would be that he also heard him whispering magical spells if he heard him murmuring to the bloody horse. “Also, only you would choose such a ridiculous name.” He muttered. Merlin swallowed. This wasn't a problem at all, right? Right.OrMerlin knows Arthur well. Better than he knew himself apparently. What he hadn't expected was for Arthur to know his servant just as well... This causes problems. (also known as "The Time Merlin Had a Mental Breakdown Over Arthur Being a Normal Human")
Relationships: Allusions to past relationships - Relationship, Merlin & Arthur Pendragon (Merlin), Merlin/Arthur Pendragon (Merlin)
Comments: 110
Kudos: 3828
Collections: Fics I read in 2020 ATiredArtist, one hole shy of perfection





	When You Know, You Know

Merlin knew Arthur well.

Of course, he did. How could he not? It was his job to know - both as a servant and as a protector. He knew what the sharp rise of his breath meant down to the twitch of his fingers. After years of trial and error in regards to figuring out Arthur’s various temperaments, habits, thoughts, and never-ending whiplash of moods he had finally nailed it. It was quite useful, really. Merlin never did learn those stupid hand signals he liked to use on quests and hunts, but could figure it out based on where Arthur’s eyes flicked or where his feet were facing.

What Merlin had not been expecting was for the vice versa to be true.

"You know that’s a horrid habit." Arthur said without looking up from examining his armor. Merlin paused, a little bewildered by what he was talking about until he looked down at where his thumb was bright red from him having just been biting at it. Slowly, he lowered his hand down, a little mystified at how Arthur knew he was doing it when Merlin hadn’t noticed.

"It isn’t a habit." He said instead with a frown. Arthur turned to look at him with raised brows. Merlin’s frown turned into an outright scowl. "It isn’t." He insisted and Arthur’s expression melted into a dangerous grin that only raised Merlin’s annoyance.

As it should. Because Arthur made a point to point it out for the rest day. Turns out Merlin did do it a lot - and the damn prat knew every single freaking time. It was a little impressive. At one point, the door had swung open while Merlin was mulling over a speech to reveal George who had politely informed him that Arthur (who was on the other side of the castle) had sent him to request that Merlin consider keeping his fingers out of his mouth. Merlin, who was outraged by such a call out, had forced George to carry back the message that Merlin’s fingers were only a peril because he was always touching Arthur‘s things. 

Arthur later informed him that George had stuttered out the message on the verge of tears in front of the entire council.

"It isn’t my fault he didn’t use discretion," Merlin snorted "I mean, he’s very proper. I’m surprised he didn’t wait to get you alone." He said, dodging a cup Arthur had thrown.

"You probably scared him. And you shouldn’t be speaking to me that way anyways-"

"I didn’t scare him. I’m not scary." Merlin objected as Arthur threw up his hands.

"Don’t interrupt me!" He said with his patented I’m-the-king-stop-vexing-me tone. "And you’re not scary, but George is one of the few people who might actually fold under your squirrelly face of annoyance."

"My what?" Merlin spluttered and Arthur gave a horribly sweet smile as he reached over to give a condescending bop to the end of Merlin's nose. 

"That’s the one!" He beamed “I’m sure it had poor George cowering in fear." He said in fake sympathy. Merlin felt his face heat up, annoyance rising. He spluttered for a moment, trying to find his special pocket of patience he had reserved specifically for Arthur.

From that point on, he decided to test exactly how well Arthur really knew him. After all, this could be a precarious situation given that Merlin was a fairly secretive person.

The results were not looking too good.

Merlin was finding out things he hadn’t even noticed about himself which was alarming. Just as he was prepared for Arthur’s every need, Arthur was apparently prepared for every one of Merlin’s mishaps and requests.

"Yes, you can go."

“What?" Merlin asked, pausing as he let the door click shut behind him. Arthur flipped over another report.

"Your mother. Her birthday. Ealdor.” He murmured, giving a slight wave as if that might expand upon his point.

"I hadn’t asked about that yet." Merlin frowned and Arthur finally looked up at him. Merlin had been actually planning to ask that very evening which is what made the whole thing that much more of a concern. 

"You ask around this time every year."

“Well...Yeah, but you couldn’t have known that I was coming here to ask that."

"But I did."

Merlin wasn’t sure how he felt about this development. And now that he was paying attention to it, the whole thing was much worse than he imagined... In ways he hadn’t quite ever put together before. He always knew what excuse Merlin was going to use to explain his absence, always knew when Merlin wasn’t paying attention, always knew when Merlin was about to hand him something even if he was a good few yards away... _Always._ Most of the time, they didn’t even need to speak to each other to do most tasks. Merlin wasn’t sure when they had gotten to this point.

"Here," Arthur said one day, pushing a bowl to him. Merlin glanced down with his brows raised to see a bunch of blueberries. No. No way. This is where he drew the line. "Try not to choke." He added absently as he shifted through more papers. Merlin looked back down at the bowl.

"Why are you giving these to me?" He demanded. Arthur frowned, eyes flicking up from his work to stare blankly at him.

"What?"

"It's your food. You eat it." Merlin continued and pushed the bowl back. Arthur stared. "You used to eat blueberries all the time. Why did you stop, anyways?" He asked, realizing with a sense of horror that it actually had been years since he had seen Arthur eat a single blueberry. He almost always gave them to Merlin.

"What are you talking about?" Arthur asked, setting is quill down to look him up and down. "You always steal them from me. I figured it was just easier to let you have them." He said. Merlin took a long breath. Okay. That... Was maybe okay. He hadn't said what Merlin was most worried about. It's not as if he knew that blueberries were - "And since when do you complain that I give you your favorite food?"

God _fucking_ damnit.

"THEY AREN'T MY FAVORITE!" Merlin burst out and before Arthur could even think about putting him in the stocks, stormed out of the room.

Things after that didn't improve. Merlin could tell that Arthur was growing increasingly bewildered by his sudden interrogations... but he couldn't help it! Exactly how much did Arthur know about him anyways? That wasn't _fair_. Merlin was supposed to know Arthur's favorite food. He was supposed to know what clothes he preferred to wear and the stupid habits he had. There was absolutely no reason for this to reciprocated. And, sure, Gaius had pointed out that Arthur spent years with Merlin next to him and was bound to pick up a few things. A _few_ things. This did not feel like a few. How dare he? What kind of game was this? Did the man have no concept of privacy?

"You can take Daisy out to fetch the cloak-"

"How do you know that?"

Arthur closed his eyes, expression riddled with irritation before turning to look at Merlin expectantly.

"Know what?"

“The mare I use. You know I call her Daisy? I never told you that." Merlin explained. Arthur stared for a few moments. He could see the flicker of emotions pass easily over him. Anger, annoyance, exasperation, indignance, and finally acceptance...AKA the Five Stages of Grief (Pendragon Edition).

"You talk to the horse.” He pointed out. Merlin narrowed his eyes.

“I whisper to the horse."

"....am I supposed to not hear it?” Arthur asked. Merlin wondered how likely it would be that he also heard him whispering magical spells if he heard him murmuring to the bloody horse. “Also, only you would choose such a ridiculous name.” He muttered. Merlin swallowed. This wasn't a problem at all, right? Right.

There were also strange coincidences that Merlin was starting suspect were not coincidences at all. If Merlin was hungry then Arthur always had leftovers. If Merlin was tired then Arthur suddenly found his presence too annoying to be around. If Merlin was wounded... Well. That was something that was becoming an increasingly pressing problem. 

“How does one fall down the stairs twice in one week?" Arthur asked. His tone was light. Amused even...But Merlin knew him too well not to miss the sharpness of his eyes and slight purse to his lips.

"You have to have my special talents, sire.” Merlin said brightly and tried to think of anything and everything that could give him away. It was like a new game of conversational chess. He wasn’t sure how well Arthur could read him actually...But it clearly was better than what he felt prepared for.

“And what are those special talents?" He asked innocently "Talking when you aren’t supposed to?"

Ah. Okay. Good. He thinks someone pushed him down the stairs then. It wasn’t ideal that the king thought someone was out for his servant but it wasn’t as bad as the truth of Merlin fighting Arthur's enemies in secret. Besides, it wasn’t like anything could come of that suspicion.

At least Merlin thought so until later that night. 

"Merlin is lying to me." 

That was fine. Totally fine. Arthur asking his knights in the midst of the darkness if they knew anything wasn’t anything to get worked up about.

"He’s injured again...And wants me to think someone else is doing it to him."

Fuck. God fucking _damnit_ Arthur. Merlin had to cover his mouth to keep from growling in frustration. He never got a break, did he?

"What? You think he’s doing it to himself?" Gwaine’s voice answered. Arthur went silent for a few moments.

"I’m not...Sure. I mean, he never said it was anyone else-“

“Then why do you think that he wants you to think that?”

“I...” Arthur paused for a moment, shifting uncomfortably before giving a meager shrug. “He, Um. Well. He did the ear thing." He said a little helplessly. Merlin’s mouth fell.

"He did what now?" 

Arthur groaned.

"You know! Whenever he lies he always yanks at his ears like the idiot he is!” Arthur said impatiently "He’s stopped doing it for the most part, but when he’s trying to make me think he’s lying...Why are you looking at me like that?" Arthur asked. Merlin could only glower indignantly from his hiding spot. He had...A few nervous habits that he had learned to iron out when he first came to Camelot. He thought nobody had noticed them, but just in case he tried to use it to his advantage. It bothered him that Arthur had not only picked up on it but also knew Merlin purposely did it to throw him off now. 

That son of a bitch had to know he had magic, right? 

“I... Nothing, my lord.” Gwaine snorted “So if nobody is hurting him then what’s with all the bumps and bruises?"

"I don’t know! That’s why I’m asking you to follow him!" Arthur snapped. Okay. Merlin was going to be tailed. He could navigate that. Probably. It was going to be really annoying.

And for the first few days after that it was. It was hard to act like he didn’t notice Gwaine always in the shadows and even harder to escape him without revealing that he knew what was going on or accidentally roping him into magical messes by mistake. Luckily, it was fine and Arthur seemed to let the matter drop after a week or so. 

Good. Because now it was Merlin’s turn.

If Arthur was going to play games then Merlin was going to win. That was only fair (because he had long decided that fairness involved Merlin winning to counterbalance all the times he had lost). Besides, there now seemed to be a very real threat of the king knowing about his magic and that was pretty terrifying to say the least.

"I know that you’re following me, Merlin."

Well then. Nevermind. 

"You had Gwaine follow me first." Merlin sighed, jumping down from the ledge he had been sitting on as he watched Arthur push back his hood instead of exiting the castle.

"Yes because you were up to something-"

“Says the one sneaking out of the castle in the middle of the night! There isn’t even anyone to stop you now. I thought you stopped doing that since becoming king.” He said, a little indignant. He was a little thrown off by what caused this escapade. Usually he could predict when Arthur might leave but if he was honest he really wasn’t sure what this was. 

"I’m only sneaking off because I knew you would follow me."

Ah. Right. Well then. 

This just got a bit more awkward. 

"And why do you want me to follow you?" Merlin asked, trying to collect himself after being so obviously thrown. Arthur’s eyes narrowed.

"Because you’ve been acting strange, Merlin! I at least wanted to see if you were still yourself enough to tail me whenever I leave the castle.” He snapped and crossed his arms. "What’s wrong with you? Are you being threatened? Are you sick?" He asked, looking Merlin up and down critically.

Huh. In theory...It was good that he was asking questions, right? Right. He couldn’t know that he had magic then. 

...Except someone who left the castle for the sole purpose to knowing Merlin would follow him had to have figured out the magic. Arthur wasn’t _that_ dense. Or was he? No, definitely not. Maybe. Actually, Merlin felt he should have an accurate knowledge of how dense Arthur was. He knew the man was pretty smart, but sometimes missed oblivious things.

 _Wait_. Did he missed oblivious things or was he pretending to because he _knew?_

This was getting out of hand.

"I’m worried... At how well you know me," Merlin finally sighed, holding up his hands in surrender. "It concerns me that you might know things I would rather you...Not know." He said. Arthur blinked.

"Well, of course I know, Merlin. Did you think I would miss it?" He asked. Merlin pointed a finger at him.

"See. No. You need to tell me what you know because I feel like you’re being way too calm to actually know." He warned. Arthur groaned.

"Are you serious?" He asked, running a hand over his face “I’m losing sleep over this? Merlin. You’re by my side constantly. You aren’t actually that discreet either." He added. Merlin shook his head.

Nah...He changed his mind. No way he knew! He wouldn’t be this goddamn conversational about it. He must think it was something else. 

"Say what it is then."

"Fine," Arthur sighed and looked around to ensure the corridor was empty. Slowly, he leaned in, gesturing Merlin closer. Merlin also leaned in. "You’re an idiot." He whispered. 

"Stop it!" Merlin practically shrieked as he tugged at his hair in pure frustration. "Do you or do you not know?"

"I don’t know!" Arthur threw back with what looked to be equal frustration. “What do you think I know?" He asked and Merlin could have burst into tears. He wasn’t even sure he knew up from down anymore. There was a slight pause as they regarded each other warily. Finally, he figured it was time to just... Rip off the bandages. Clearly, Arthur already knew more than he was letting on. He took a deep breath.

"I have magic-"

"You’re having an affair." Arthur said at the same time. Merlin froze.

"I’m having an affair.”

"You have magic?!"

Merlin probably deserved this.

"Wait," He said, waving his hands before the fear and panic could fully sink in. "Who the Hell do you think I'm having an affair _with?"_ He asked. Arthur was staring at him with wide eyes. This perhaps wasn't the best thing to ask given that Arthur could very well kill him with what Merlin had just admitted to but... He felt this was a good question nevertheless.

"I don't know. Everyone?" Arthur said slowly and shook his head "I thought that was probably why Gwaine didn't come back with anything while he tailed you-"

"You thought I was having an affair with _Gwaine?"_

"And Lancelot. And Gwen. And maybe Morgana at some point too-"

"None of these people are married," Merlin frowned, rubbing the back of his head "So I don't think it qualifies as an affair anyways. Well, I guess if any of us were in a relationship it would qualify, perhaps. But I'm not. And Lance wasn't. Neither was Gwaine or Morgana. You and Gwen had your thing going on but I'm not sure if you and her actually got together or not so I would never even consider-"

"Are you going to explain the magic or not?" Arthur interrupted. Merlin flinched. It would be his own stupidity that ratted him out. Gaius was going to _kill_ him. He glanced up, using years of studying Arthur to figure out what exactly he was thinking. For whatever reason, he felt himself coming up blank. He couldn't see any anger there... Or acceptance. Just a silent twitch of his lips that demanded an explanation. Merlin felt his resolve harden.

"I was born with it," He said, keeping his tone as even as possible. "I can't help that I have it and I've been using it to protect you for years. I've lied to you and I... I haven't been completely honest with who I am, but I had no choice in the matter. I wasn't going to put you in the position to choose between your father and myself and if you killed me then I couldn't protect you anyways." He said and took another deep breath. "I understand if you're upset with me, but I think I made the right decisions for the most part and I would like you to consider that."

The words were unapologetic. Stern. Completely unyielding even in the face of certain persecution. Part of him was proud that there wasn't an ounce of fear in his voice.

"You don't need to be scared."

And apparently Arthur saw right through him. Figures.

"You're upset." Merlin said in return. It wasn't a question. Despite Arthur's composure Merlin could just... Tell. His jaw was clenched slightly. Hands hidden under his cloak so Merlin couldn't see the way they clenched. He was staring at Merlin as if seeing him for the first time.

"I am," Arthur agreed quietly and ran a hand over his face "I really would have preferred you having an affair." He muttered. Merlin gave a nervous laugh.

"Well...While we're being honest... I never exactly denied it. I just don't think affair is the right term-"

"Stop talking."

"Yeah, alright." Merlin nodded. That was fair. Understandable. "Are you going to kill me?" He asked, biting his lip. Arthur looked at him and Merlin could have kicked himself at the flash of hurt that came over Arthur's face.

For saying he knew Arthur so well.... Maybe Merlin didn't see the most obvious thing about him. How many people had Arthur condemned to death within their time of knowing each other? Even in the beginning he had helped sneak Mordred out. Had trusted Morgause. Hell, Merlin was fairly certain that if Will had lived than he wouldn't have killed him. Arthur had sought up Dragoon's help and...

"Figuratively or literally?" Arthur asked dryly. Merlin offered a wry smile. "I thought I knew you." He added, voice growing quiet towards the end. Merlin gave a short laugh.

"Oh, trust me. This entire experience has proven that you do." He said and absently bit at his thumb. "You really picked up on the ear thing?" He asked and at Arthur's baffled expression shrugged. "I overheard you and Gwaine. You talked about my lying." He said and tugged at his ear to demonstrate the tick. Immediately, the king's expression cleared.

"Don't be flattered. It's only because you're obvious." He grumbled and crossed his arms over his chest. "Besides, nowhere in your job description does it say you need to know when I'll be sneaking out of the castle." He added with a gesture towards the empty hallway. Merlin rolled his eyes.

"It does in my other job actually." He sniffed. Arthur narrowed his eyes. "What? I can't really defend you if you're mucking about by yourself, can I?" He added on defensively. He had hoped the conversation might flow easily now that the secret was out - surely in his imaginings of this moment he had pictured a lot more words being said. Angrily and loudly, yes, but still more words all the same. Now things felt...Awkward? Forced? Like if Merlin stopped talking they might just stand there forever without ever speaking again. "I should tell you everything." He found himself rambling as he wrung his hands together. "About why I came here and the magic and dragon - oh yeah. There's a dragon. And my father, of course, you should know about him and Morgana and Lancelot and the Questing Beast and Nimueh. Oh, your father. I should talk about your father, definitely. Maybe I should just start from the beginning? Or you could need more time to digest and -"

The words were stopped by Arthur walking over to put a hand over his mouth.

"I thought I said for you to stop talking." He told him, though Merlin caught the touch of amusement underneath the layers of frustration and annoyance. "We shouldn't be doing this in the hallway." He groaned and let his arm fall, trailing down to Merlin's wrist. He tugged him over and Merlin could only follow as they went back down the labryinth of corridors. There were glimpses of guards easily avoided and knights they dodged with practiced ease. Merlin thought they might make it back towards Arthur's rooms (that was definitely where Arthur was leading them to, he was certain) without incident.

Yeah... Incorrect.

"Another poetry lesson?"

Damnit.

"Leon," Arthur said and turned. The knight was watching them with a torch in hand, illuminating a rather exasperated expression as his eyes flicked down to where Arthur's hand was still pulling Merlin along. "We... We were..." He looked back at Merlin who shrugged. "Yes." He said, voice lowering in defeat. "Poetry. Again." He muttered. Leon nodded.

"You have quite the appetite for it, my lord."

"Um... Yes. Poetry is... Very good."

"I'll leave you to it then," Leon nodded and gave them one more glance before shaking his head "Besides, it appears I owe Gwaine some money." He added. Merlin only just caught the words muttered under his breath (and based on Arthur's expression he did as well). There were a few seconds were they both stood there.

"He doesn't think we're reading poetry, does he?"

"No, absolutely not." Merlin agreed. Arthur sighed and opened the door.

"Shouldn't surprise me given that you apparently have gotten around."

" _Hey-"_ Merlin spluttered before being pushed into the room. "You don't even know-"

"Definitely Lancelot or Gwaine. Maybe both?" Arthur asked. Merlin opened his mouth and then promptly closed it. "There was also someone who I don't know about... I think. Whoever you always pick those strawberries for." He added absently and Merlin almost tripped over his own feet. Arthur knew about that? He thought he had been pretty discreet with his visits to Freya's resting place. "What?" He asked with a tilt of his head. "You always get a stupid dopey look on your face when you like someone." He added and yanked off his boots.

This seemed like a surreal conversation to have in the wake of Merlin's magic, but hey. He'd bite.

"Not much happened between Freya and I before she died," He said and there was a flicker of surprise on Arthur's face at the name. "Also, don't act so uppity. I can tell when you like someone too. Gwen and Mithian." He said. Arthur made a face.

"Can you?" He asked. "Go on then. What are my tells?"

"Not really much to say on tells. You just have a type. Anyone who is brave enough to speak their mind to Arthur Pendragon will automatically earn his favor."

"That has some truth to it," Arthur mused and sat down in one of the armchairs. "You speak your mind to me quite often." He added. Merlin didn't bother to wait for an invitation. After all, if he wasn't getting beheaded for magic than he was pretty sure he was immune to the smaller laws in place as well.

"I don't think I've ever seen you fancy a man." Merlin scoffed. Arthur leaned forward and flicked his wrist. Oh. He was biting his thumb again. With a scowl, he lowered it before staring at the crackling fire. That was a weird thing to point out. What was the point of bringing up Merlin's name among Gwen and Mithian? He glanced back at Arthur for a second to put years of training to use. To look at his hands and feet. The rise of chest the way he shifted nervously and - "Oh." Merlin interrupted his thoughts. Huh.

"What?"

"Nothing."

"No, you thought of something. What is it?" Arthur asked, kicking him. Merlin bit back a grin and shook his head. "I've changed my mind. You should be beheaded for sorcery." He muttered, ignoring Merlin's growing grin. " _What?"_

"I do often speak my mind to you, huh?" He asked. Arthur immediately went red. Fascinating.

"You should probably start by explaining how you got magic. Were you cursed? Or-"

"You're blushing."

"It's hot in here. We're by a fire. Be quiet."

"You don't get that red by a fire normally." Merlin said with a feigned frown and leaned forward to put a hand on his head "Are you sick, maybe? Don't feel a fever." He added and Arthur shoved his hand away with incoherent mutters. Merlin's smile grew. He did know Arthur very well after all. He knew exactly what the twitch of his fingers meant along with the lack of eye contact and tension in his shoulders.

He would leave it alone for now though. If, after Merlin finished his tale of magic, murder, and treason, Arthur still wanted him around then... Maybe Merlin would stop hiding his 'dopey smiles' after he left room. It might tip him off to a thing or two... After all, Arthur knew Merlin pretty well too. Perhaps even better than a king should know his servant. 

Maybe Merlin didn't mind it so much after all.


End file.
